Iran marks National Nuclear Technology Day, signaling defiance of the US Iran marks National Nuclear Technology Day, signaling defiance of the US While the event is held annually in Iran, this year it coincided with a meeting in Vienna between Iran and the Joint Committee on the Nuclear Agreement. By Michael Segall A poster marking Iran’s Nuclear Technology Day shows the nuclear scientists killed on the way to realizing Iran’s advance in the military and civilian nuclear field—to the right of the Supreme Leader Ali Khamenei is a picture of Mohsen Fakhrizadeh, Iran's assassinated nuclear chief. Credit: Iranian press.